DRF 3 - 使用尽管表创建多对多更新/创建序列化程序

Question

我正在尝试在DRF 3中创建一个参考应用程序来演示可以创建/更新模型的嵌套序列化程序.下面的示例代码在**之后使用"*create()参数进行炸弹,在尝试创建嵌套模型时必须是映射,而不是列表*".我也不清楚我如何处理.update(),因为在某些情况下我只想建立其他关系(人).

样本模型:

from django.db import models
class Person(models.Model):
    name = models.CharField(max_length=128)
class Group(models.Model):
    name = models.CharField(max_length=128)
    persons = models.ManyToManyField(Person, through='Membership')
class Membership(models.Model):
    person = models.ForeignKey(Person)
    group = models.ForeignKey(Group)

以及序列化器和视图集:

from rest_framework.serializers import ModelSerializer
from rest_framework.viewsets import ModelViewSet
from app.models import Group, Person
class PersonSerializer(ModelSerializer):
    class Meta:
        model = Person
class GroupSerializer(ModelSerializer):
    persons = PersonSerializer(many=True)
    def create(self, validated_data):
        persons = validated_data.pop('persons')
        group = Group.objects.create(**validated_data)
        if persons: # Bombs without this check
            Person.objects.create(group=group, **persons)  # Errors here
        return group
    class Meta:
        model = Group

class PersonModelViewSet(ModelViewSet):
    serializer_class = PersonSerializer
    queryset = Person.objects.all()

class GroupModelViewSet(ModelViewSet):
    serializer_class = GroupSerializer
    queryset = Group.objects.all()

我正在尝试POST一些JSON,它插入一个具有两个(相关)人员的组:

{
   "persons": [
      { "name" : "name 1" },
      { "name" : "name 2" }
   ],
   "name": "group name 1"
}

Answer 1

使用PrimaryKeyRelatedField此处显示:

http://www.django-rest-framework.org/api-guide/relations/#primarykeyrelatedfield

class GroupSerializer(serializers.ModelSerializer):
    persons = serializers.PrimaryKeyRelatedField(
        many=True, queryset=Person.objects.all())

    class Meta:
        model = Group
        fields = ('name', 'persons')

例如,首先创建每个人.ID为1的人,姓名="Bob".ID为2的人,姓名="Tim".然后使用primary keys So 将它们发布到REST端点:

# Group create() REST endpoint data to POST
{'name': 'my group', 'persons': [1, 2]}

现在,您之前创建的人员是该组的一部分.

Answer 2

我不知道是否有更简单的方法,但我设法使其工作的唯一方法是在组序列化器中引用"直通"模型"成员资格"并为.create()和.update编写自定义代码( ).这似乎只是设置M2M FK的很多工作.如果有人知道更好的方式我会喜欢听到它.

class GroupMembershipSerializer(ModelSerializer):
    class Meta:
        model = Membership
        fields = ('person',)

class GroupCreateSerializer(ModelSerializer):
     memberships = GroupMembershipSerializer(many=True, required=False)

    def create(self, validated_data):
        person_data = validated_data.pop('memberships')
        group = Group.objects.create(**validated_data)
        for person in person_data:
            d=dict(person)
            Membership.objects.create(group=group, person=d['person'])
        return group

    def update(self, instance, validated_data):
        person_data = validated_data.pop('memberships')
        for item in validated_data:
            if Group._meta.get_field(item):
                setattr(instance, item, validated_data[item])
        Membership.objects.filter(group=instance).delete()
        for person in person_data:
            d=dict(person)
            Membership.objects.create(group=instance, person=d['person'])
        instance.save()
        return instance

    class Meta:
        model = Group

class GroupCreateModelViewSet(ModelViewSet):
    serializer_class = GroupCreateSerializer
    queryset = Group.objects.all()

因此,您可以使用以下方法创建一个包含相关人员的新组:

 { 
     "name" : "Group 1", 
     "memberships" : [ 
         { "person" : 1 },
         { "person" : 2 }
     ]
 }